Researcher Amy Muise, who is also an assistant psychology professor at Toronto's York University, explains, “Sex is associated with feeling more satisfied in a relationship,” which is why people who regularly have intercourse experience greater levels of happiness.

However, it’s surprising to note that a couple's happiness is not further increased the more times they have sex per week. While there's nothing wrong with increasing the frequency, “it just doesn’t seem to make couples any happier,” Muise says.

Watch the video above to hear more.

Interestingly, a recent study revealed that U.S. couples are actually having less sex now than they did in the 1990s and 2000s.

According to San Diego State University psychology professor and study co-author Jean Twenge, one of the reasons behind this decline is Netflix and YouTube.